Network nodes and methods for transmitting low-latency data in a radio communications system

ABSTRACT

The present invention refers to methods and network nodes transmitting data in a radio communications system. In particular, the present invention refers to a method including the steps of receiving a portion of a data unit; and starting a processing of the portion of the data unit prior to receiving remaining portions of the data unit, and to a network node configured for executing the method.

FIELD OF THE INVENTION

The present invention relates to transmitting data in a radiocommunications system. Particularly, the present invention refers tomethods for the transmitting; and network nodes configured to performthe transmitting.

BACKGROUND OF THE INVENTION

In current system designs for mobile or wireless communication, inparticular in the context of the 3^(rd) Generation Partnership Project(3GPP), there is a clear tendency to optimize the standardized systemprimarily for maximum spectral efficiency and maximized data throughput.Additionally, latency is a key issue as well, which is also underconsideration when specifying systems and their operation.

One-way latency in a communications system is defined as the delay fromwhen a data packet is available for transmission in one end until it isavailable for further processing in the receiving end, while two-way orround-trip latency is the sum of the latencies in both directions, e.g.the time it takes for a response on a packet to become available at thetransmitter of that packet.

Latency will limit the achievable data rate, and is inherent in allprotocols, as e.g. TCP/IP, for basically all applications. As anexample, whenever a handshaking between peers on both sides of acommunication line is needed e.g. in a request-response way, one peerneeds to wait until information is sent to the other peer andsubsequently the answer is received. This waiting time, i.e. thelatency, limits the achievable throughput in practice, even if anunlimited amount of data could be sent per time interval.

Latency is in particular an issue for multi-hop or relaying systemswhere data have to transverse several hops where each link between nodeswill have its own individual Hybrid automatic repeat request (HARQ)loop, but latency could also be an issue for conventional single hopsystems.

There are several ways to increase throughput, partly by increasing thespectral efficiency but mainly by exploiting more resources, e.g. usingmore base stations, more spectrum and more antennas per base station anduser equipment (UE).

It is much harder to improve latency: the main tools are to reduce thetime span of a physical layer packet (smaller Transmission Time IntervalTTI, currently 1 ms in LTE after 2 ms in HSDPA and 10 ms in UMTS),decrease cell sizes in order to reduce the travel time of the signals(speed of light), or more generally put peer nodes as close as possibleto the UE (e.g. from RNC in UMTS to the eNB in LTE) and to do theprocessing in the nodes quicker. The first cost spectral efficiency dueto increased control overhead, while the second requires more basestations and more functionality to be implemented in them and the lattercosts more powerful processing elements.

It is therefore a problem to reduce the latency in current communicationsystems, and thus there is still a need for an improved method forprocessing data in a radio communications network.

SUMMARY OF THE INVENTION

Object of the present invention is improving of data transmission in aradio communications system.

This object is achieved by a method for transmitting data in a radiocommunications system comprising the steps of receiving a portion of adata unit; and starting a processing of the portion of the data unitprior to receiving remaining portions of the data unit.

As an advantage of the method the overall transmission latency in theradio communications network is improved.

According to some embodiments of the present invention, the processingcomprises a forwarding of the portion of the data unit.

According to further embodiments of the present invention, the methodfurther comprises the step of checking the data unit for eligibility forfurther processing.

As an advantage, the method allows for a low latency yet robustsignaling scheme by checking the eligibility of the data unit.

According to further embodiments of the present invention, the methodfurther comprises the step of receiving a further portion of the dataunit, wherein the step of checking is based on the further portion ofthe data unit.

According to further embodiments of the present invention, the checkingcomprises checking of each received portion of the data unit.

As an advantage, each transmitted portion of the data unit can bechecked individually regarding its eligibility, as well as the data unitas a whole.

According to further embodiments of the present invention, the methodfurther comprises one or more of the following steps of:

-   -   sending a speculation indication, the speculation indication        indicating a possible recalling of the data unit in case that        the checking results in the data unit not to be considered        eligible for further processing;    -   sending a confirmation indication, the confirmation indication        indicating that the checking results in the data unit being        considered eligible for further processing;    -   sending a cancellation indication, the cancellation indication        indicating that the data unit and/or any portion of the data        unit is to be cancelled;    -   sending an instruction for preferred processing of the data        unit, indicating a preferred processing of the data unit;    -   sending an instruction for deferred processing of the data unit,        indicating a deferred processing of the data unit; or    -   sending, in case of the checking indicating that a previously        received portion of the data unit is not considered eligible for        further processing, a corrective information, the corrective        information allowing for correcting the previously received        portion of the data unit.

As an advantage, the overall system latency is reduced as processing ofthe data unit, or at least processing of portions of the data unit, canalready start prior to receiving the complete data unit. In case of adata unit which later turns out not to be eligible for furtherprocessing, the speculation indication allows to prepare for a latercancelling, thereby reducing the processing time necessary for theactual cancelling and avoiding non cancellable or non revertibleeffects.

According to further embodiments of the present invention, the methodfurther comprises the step of assigning an identification to the dataunit, the identification allowing to uniquely identify the data unit.

As an advantage, portions of the data unit as well as speculationindications, confirmation indications, cancelling indications orinstructions for preferred or deferred processing can easily be linkedto the respective portions during the processing.

According to further embodiments of the present invention, the methodfurther comprises the step of assigning a likelihood value to the dataunit, the likelihood value indicating a likelihood for a need for acorrection or a cancelling of the data unit.

As an advantage, it is possible to take precautions regarding a possiblecorrecting or cancelling of the data unit and assign processingresources more optimally by prioritizing such data units that have alower risk of requiring cancellation or correction later on.

The object of the present invention is also achieved by a method fortransmitting data in a radio communications system comprising one ormore of the following steps:

-   -   forwarding, upon receiving a portion of a data unit comprising a        speculation indication, the portion of the data unit, and        preparing for a possible cancelling of the data unit;    -   postponing, upon receiving a portion of a data unit comprising a        speculation indication, a forwarding of the portion of the data        unit until a confirmation indication is received;    -   forwarding, upon receiving a confirmation indication, the        portion of the data unit and any previously received, postponed        portions of the data unit;    -   cancelling, upon reception of a cancelling indication, the data        unit and/or any portion of the data unit;    -   correcting, upon receiving a corrective information, a        previously received portion of the data unit which is not        considered eligible for further processing, and forwarding the        corrected previously received portion of the data unit; or    -   finalizing, upon complete reception of the data unit, the        transmitting of the data unit.

As an advantage of the method, the overall transmission latency in theradio communications network is improved.

According to some embodiments of the present invention, the methodfurther comprises the step of interpreting, after a defined time or uponcomplete reception of the data unit, a missing of a cancellationindication in the data unit as a confirmation indication for the dataunit.

As an advantage, signaling overhead is reduced, as it is not necessaryto send an explicit confirmation indication, and instead interpret theabsence of a cancelling indication after a certain, defined time or inthe last portion of the data unit as confirmation indication.

The object of the present invention is also achieved by a network nodeconfigured for transmitting data in a radio communications system, thenetwork node comprising:

-   -   receiving means configured for receiving a portion of a data        unit; and    -   processing means configured for starting a processing of the        portion of the data unit prior to receiving remaining portions        of the data unit.

As an advantage of the network node, the overall transmission latency inthe radio communications network is improved.

The object of the present invention is also achieved by a network nodeconfigured for transmitting data in a radio communications system,comprising one or more of the following:

-   -   forwarding means configured for forwarding, upon receiving a        portion of a data unit comprising a speculation indication, the        portion of the data unit, and preparing for a possible        cancelling of the data unit;    -   postponing means configured for postponing, upon receiving a        portion of a data unit comprising a speculation indication, a        forwarding of the portion of the data unit until a confirmation        indication is received;    -   forwarding means configured for forwarding, upon receiving a        confirmation indication, the portion of the data unit and any        previously received, postponed portions of the data unit;    -   cancelling, upon reception of a cancelling indication, the data        unit and/or any portion of the data unit;    -   correcting means configured for correcting, upon receiving a        corrective information, a previously received portion of the        data unit which is not considered eligible for further        processing, and forwarding the corrected previously received        portion of the data unit; or    -   finalizing means configured for finalizing, upon complete        reception of the data unit, the transmitting of the data unit.

As an advantage of the network node, the overall transmission latency inthe radio communications network is improved.

Further embodiments of the present invention are provided with thecorresponding dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more clearly understood from the followingdescription of the preferred embodiments of the invention read inconjunction with the attached drawings, in which:

FIG. 1 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 2 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 3 shows an implementation of the present invention according tosome embodiments of the present invention.

FIG. 4 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 5 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 6 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 7 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 8 shows an implementation of the present invention according tosome embodiments of the present invention;

FIG. 9 shows an implementation of the present invention according tosome embodiments of the present invention; and

FIG. 10 shows an implementation of the present invention according tosome embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the present invention, it is proposed to introducespeculative processing and speculative communication into mobile orwireless communications systems, in particular to protocol stacks.Communications in such a communications system is mainly done on dataunits, or data packages. Typical examples are so-called protocol dataunits (PDUs). However, the present invention applies to any kind of dataunits to be transmitted from one network node, or sender, to anothernetwork node, or receiver. The transmitting of data units canfurthermore comprise a relay node, or hop, which acts as a receiver inone step of the method and as a sender in a further step of the method,as it receives a data unit transmitted from the original sender andforwards the data unit to the final receiver.

Typically a network node, or protocol entity, only starts processing ofa PDU after the PDU has been fully received from the next lower orhigher or peer protocol entity. According to some embodiments of thepresent invention, it is proposed to already start early to forwardpartial PDUs, or portions of a data unit, to the next protocol entity toallow that one to start working on the initial part, or portion, of thePDU as well.

Accordingly, FIG. 1 shows a method for transmitting data in a radiocommunications system. The method comprises the steps of receiving 11 aportion of a data unit, and starting a processing 12 of the portion ofthe data unit prior to receiving remaining portions of the data unit. Itshould be noted that already the first network node, or protocol entity,in a chain receives a portion of a data unit, e.g. from a data source,another protocol layer, or a user.

According to further embodiments, as shown in FIG. 1, the processing 12further comprises a forwarding 121 of the portion of the data unit. Thisapplies, for instance, in case of a relay node, or hop, involved in thetransmitting.

According to further embodiments of the present invention, as shown inFIG. 2 the method further comprises the steps of receiving 13 a furtherportion of the data unit, and checking 14, based on the further portionof the data unit, the data unit for eligibility for further processing.A typical example is an approach called Cyclic Redundancy Check (CRC),which adds information at the end of a data unit, or packet, that isused to identify and catch incorrectly received data units. According tosome embodiments of the invention, the further portion of the data unitcomprises control data.

However, it is not necessary to receive the further portion of the dataunit in order to check the data unit for eligibility for furtherprocessing. The checking is also possible based on other measures.Examples are cases where there is some additional side informationavailable on the data. One example would be multiple CRC sums whichcover only part of the data unit, or a pre-knowledge on certain aspectsof the data unit e.g. some fields may only contain values of a certainpredefined range to be eligible. Then a data unit can be determined notto be eligible based only on parts of that data unit e.g. if there is afield with illegal value or a partial CRC sum doesn't match. On theother hand some parts of a data unit may have any content, say a freepayload part after the header, then there data unit can be determined tobe eligible for forwarding after checking the header as there is noconstraint on the payload and therefore no risk for an ineligiblepayload.

The checking 14 comprises, according to further embodiments of theinvention, checking of each received portion of the data unit.

In case of the checking 14 resulting in the data unit not to beconsidered eligible for further processing, i.e. the data unit beingincorrectly received or being not or no longer valid for some reason,the invention proposes to provide a kind of “emergency break” to allowto cancel processing of an already forwarded and/or speculativelyexecuted or speculatively communicated PDU in case it is determinedeventually that the PDU should not have been forwarded and/or executed.Furthermore, the invention proposes to allow for data units to beprocessed in a preferred or deferred manner, as well as for providingcorrective information to correct a previously, incorrectly receivedportion of the data unit.

In particular, as shown in FIG. 3, according to some embodiments of theinvention the method further comprises one or more of the followingsteps:

-   -   Sending 15 a a speculation indication, the speculation        indication indicating a possible recalling of the data unit in        case that the checking 14 results in the data unit not to be        considered eligible for further processing. The speculation        indication to the next entity can be used to make it aware there        may be a need to revoke the data unit. This indication can be        protocol entity and/or PDU-specific. Even before receiving the        final confirmation of the data unit, the peer can already        forward the data unit to further communication entities, again        with a speculation indication and possibly cancelling it if the        original data unit was cancelled. In a similar way the        speculation indication can be chained over different protocol        layers or entities.    -   Sending 15 b a confirmation indication, the confirmation        indication indicating that the checking 14 results in the data        unit being considered eligible for further processing. In the        case the whole data unit received by next higher or lower        protocol entity is true, the processing of the data unit is        continued as usual. For this purpose, instead of the speculation        indication, or emergency break, a confirmation information can        be sent, confirming the sent data unit is valid.    -   Sending 15 c a cancellation indication, the cancellation        indication indicating that the data unit and/or any portion of        the data unit is to be cancelled. Cancelling here can also be        understood as nullifying the data unit, or declaring it as        invalid.    -   Sending 16, 17 an instruction for preferred or deferred        processing of the data unit, indicating a preferred or deferred        processing of the data unit, i.e. the data unit is to be        processed earlier or later than other data units. When receiving        several PDUs, or data units, this allows to start processing the        ones that e.g. would be most easily corrected, i.e. one that has        only limited impact. As an example, it is proposed to rather        process an ordinary data unit that simply causes a corresponding        data unit to be forwarded to the next entity rather than a        release message that would cause a release of the connection and        significant changes to the internal states and variables.    -   Sending 18, in case of the checking 14 indicating that a        previously received portion of the data unit is not considered        eligible for further processing, a corrective information, the        corrective information allowing for correcting the previously        received portion of the data unit. In case only a part of the        data unit is false, the corrective information can be applied to        the data unit as follows: The receiver stores the partially        correctly received PDU. The transmitter (re)-transmits the        missing or erroneous (part of) the PDU or an information        allowing to correct erroneous parts. The receiver reassembles        the PDUs until a complete data unit corresponding to next        protocol entity is received. The next entity (i.e. in the        receiver) can then either decide to cancel the original data        unit and send a cancellation indication to the next entity and        instead process the correct data unit, or correct the action,        e.g. send itself a corrective information to the next entity.        The latter typically applies if the correction applies to the        data-payload rather than to the header of the data unit, while        the former would typically be done if the header happens to turn        out to have been corrupted. Errors introduced by transmission        errors on portions on the data unit, or sub-packets, which form        a PDU can also be covered by this means: the receiver does not        have to wait for the correct reception of the entire PDU but can        already react on it and (at least partially) forward it. Once        the missing portion of the data unit, or sub-packet, arrives it        is forwarded as a corrective information to the next entity to        complete the PDU that was already (partially) forwarded. Instead        of sending deliberately an erroneous portion of the data unit,        it is also possible to indicate explicitly where a part is        missing. This avoids that the next entity triggers unnecessary        actions which would most likely have to be cancelled.

Furthermore, according to some embodiments of the invention, as shown inFIG. 3 the method further comprises the step of assigning 19 a anidentification to the data unit, the identification allowing to uniquelyidentify the data unit. This is in particular helpful to link the abovedescribed indications and instructions to the respective data unit, asassigning a specific identification to a forwarded PDU enables to lateron associate cancellation or corrections to the correct PDU.Alternatively the linking can be done in an implicit way, e.g. similarlyas in a synchronous HARQ scheme.

According to further embodiments of the invention, as shown in FIG. 3the method further comprises the step of assigning 19 b a likelihoodvalue to the data unit, the likelihood value indicating a likelihood fora need for a correction or a cancelling of the data unit. I.e. it isproposed to add an indication of the likelihood that the PDU may need tobe corrected or cancelled in order to assist the peer which PDUs toprocess with priority. Basically the receiver is well advised toprioritize the data units that have a low likelihood of needing to becancelled or corrected. E.g. if two data units are receivedsimultaneously, the one that is less prone to be cancelled is forwardedfirst and only later the other ones. Prioritizing in this way the riskthat the already forwarded portions of the data unit will need to becancelled is minimized, as these units would have been forwarded invain. The likelihood that forwarded portions of data units can bemaintained is maximized; these have been then forwarded usefully.

With regard to FIG. 3, is has to be noted that the steps 15 a, 15 b, 15c, 16, 17, 18, 19 a, 19 b do not need to be executed in sequence, nor isit necessary to execute all of these steps. The asterisk indicates thatone or more of the steps 15 a, 15 b, 15 c, 16, 17, 18, 19 a, 19 b can beexecuted in any sequence, and each step can be executed once or severaltimes or not at all during the process of transmitting a data unit.

FIG. 4 shows another implementation according to some embodiments of thecurrent invention. As shown in FIG. 4, the proposed method fortransmitting data in a radio communications system comprises one or moreof the following steps:

-   -   Forwarding 21, upon receiving a portion of a data unit        comprising a speculation indication, the portion of the data        unit, and preparing for a possible cancelling of the data unit.        The following examples show how such a preparing for cancelling        can be implemented in different cases. The data unit may e.g.        cause data to be stored in a database, then the previous,        overwritten content of the database may be temporarily stored to        allow the original state of the database to be restored in case        a cancellation becomes necessary. In order to avoid further        changes to the entry in the database, the entry may be held        locked to make sure it remains available for being restored. Any        actions that cannot be reverted, e.g. deletion of entire records        in the database can be postponed to make sure the cancelling is        not impossible. Another example is that in response to the data        unit some information is to be retrieved and sent (e.g. back to        the requestor, in this case the information may already be        retrieved and prepared for sending i.e. formatted in a suitable        way but not be sent yet. In particular changes to the outside of        the device which may easily happen in control applications like        igniting an oven, detaching some physical units or printing and        ejecting some information/goods from a machine e.g. vending        machine all actions that can typically not be reverted easily,        are prepared, e.g. the oven may be pre-heated the fixture of the        unit being prepared for unlocking, the goods of the vending        machine retrieved from storage and aligned with the release        hole, but the action is not finally and irreversibly being        executed.    -   Postponing 22, upon receiving a portion of a data unit        comprising a speculation indication, a forwarding of the portion        of the data unit until a confirmation indication is received.        This is in particular applicable in case the subsequent        processing unit or step does not support handling of        cancellation indications e.g. because it is a legacy device not        having implemented the invention.    -   Forwarding 23, upon receiving a confirmation indication, the        portion of the data unit and any previously received, postponed        portions of the data unit.    -   Cancelling 24, upon reception of a cancelling indication, the        data unit and/or any portion of the data unit. The following        examples show how such a cancelling can be implemented in        different cases. In case of a database, any change being done        can be reverted, also called rerolled including any potential        subsequent changes i.e. changes that had been done in response        to the change that is cancelled. Another example is that        information that has been retrieved in response to the data unit        to be sent subsequently and prepared for sending is discarded.        Physical changes to the outside of the device are not done and        any preparations are reverted e.g. an oven is not ignited but        let cool down again, physical units are not detached but on the        contrary re-secured, and retrieved goods are not ejected but        brought back into the storage.    -   Correcting 25, upon receiving a corrective information, a        previously received portion of the data unit which is not        considered eligible for further processing, and forwarding the        corrected previously received portion of the data unit.        According to some embodiments of the invention, upon receiving a        corrective information, a previously received portion of the        data unit is cancelled, and a new, correct copy of the portion        of the data unit is transmitted.    -   Finalizing 26, upon complete reception of the data unit and/or a        confirmation indication, the transmitting of the data unit. The        following examples show how such a finalizing can be implemented        in different cases. In case of a database, any change being done        are submitted to the database and the records are unlocked so        further action can be done on the new values by other processes        and any previously stored values or information to reroll the        transaction can be discarded. Another example is that        information that has been retrieved in response to the data unit        is finally sent. Physical changes to the outside of the device        can now finally be done e.g. an oven is ignited, physical units        are detached, and retrieved goods are now ejected by the vending        machine.

FIG. 5 shows another implementation according to some embodiments of thecurrent invention. As shown in FIG. 5, the method further comprises thestep of interpreting 27, after a defined time or upon complete receptionof the data unit, a missing of a cancellation indication unit as aconfirmation indication for the data unit.

FIG. 6 shows another implementation according to some embodiments of thecurrent invention. In particular, FIG. 6 shows a network node 31configured for transmitting data in a radio communications system, thenetwork node comprising:

-   -   receiving means 311 configured for receiving a portion of a data        unit; and    -   processing means 312 configured for starting a processing of the        portion of the data unit prior to receiving remaining portions        of the data unit.

According to further embodiments, the processing means 312 are furtherbeing configured for forwarding the portion of the data unit.

According to some embodiments, the network node 31 further compriseschecking means 313 configured for checking, based on a further portionof the data unit, the data unit for eligibility for further processing.

According to further embodiments, the network node 31 further comprisesone or more of the following:

-   -   sending means 314 a configured for sending a speculation        indication, the speculation indication indicating a possible        recalling of the data unit in case that the checking results in        the data unit not to be considered eligible for further        processing;    -   sending means 314 b configured for sending a confirmation        indication, the confirmation indication indicating that the        checking results in the data unit being considered eligible for        further processing;    -   sending means 315 configured for sending a cancellation        indication, the cancellation indication indicating that the data        unit and/or any portion of the data unit is to be cancelled;    -   sending means 314 c configured for sending an instruction for        preferred processing of the data unit, indicating a preferred        processing of the data unit;    -   sending means 314 d configured for sending an instruction for        deferred processing of the data unit, indicating a deferred        processing of the data unit; or    -   sending means 314 e configured for sending, in case of the        checking indicating that a previously received portion of the        data unit is not considered eligible for further processing, a        corrective information, the corrective information allowing for        correcting the previously received portion of the data unit.

According to some embodiments, the network node 31 further comprisesassigning means 316 a configured for assigning an identification to thedata unit, the identification allowing to uniquely identify the dataunit.

According to further embodiments, the network node 31 further comprisesassigning means (316 b) configured for assigning a likelihood value tothe data unit, the likelihood value indicating a likelihood for a needfor a correction or a cancelling of the data unit.

FIG. 6 also shows another implementation according to some embodimentsof the current invention. In particular, FIG. 6 shows a network node 32configured for transmitting data in a radio communications system,comprising one or more of the following:

-   -   forwarding means 321 a configured for forwarding, upon receiving        a portion of a data unit comprising a speculation indication,        the portion of the data unit, and preparing for a possible        cancelling of the data unit;    -   postponing means 322 configured for postponing, upon receiving a        portion of a data unit comprising a speculation indication, a        forwarding of the portion of the data unit until a confirmation        indication is received;    -   forwarding means 321 b configured for forwarding, upon receiving        a confirmation indication, the portion of the data unit and any        previously received, postponed portions of the data unit;    -   cancelling means 323 configured for cancelling, upon reception        of a cancelling indication, the data unit and/or any portion of        the data unit;    -   correcting means 324 configured for correcting, upon receiving a        corrective information, a previously received portion of the        data unit which is not considered eligible for further        processing, and forwarding the corrected previously received        portion of the data unit; or    -   finalizing means 325 configured for finalizing, upon complete        reception of the data unit, the transmitting of the data unit.

According to some embodiments, the network node 32 further comprisesinterpreting means 326 configured for interpreting, after a defined timeor upon complete reception of the data unit, a missing of a cancellationindication in the data unit as a confirmation indication for the dataunit.

FIG. 7 shows another implementation according to some embodiments of thecurrent invention. In particular, FIG. 7 shows a data unit 4, comprisinga first portion 41 of the data unit 4 and a further portion 42 of thedata unit 4. As described above, the data unit is forwarded in portions.

Furthermore, FIG. 7 shows on the left side a conventional forwarding ofa data unit 4 from a first network node to a second network node. Thiscan also be called one hop forwarding, as two network nodes are involvedand the data unit has to take two hops. In the upper and lower row,portions of a data unit sent by the first and second network node areshow. Time is indicated from the left to the right in FIG. 7.

As shown in FIG. 7, conventionally, a data unit 4 needs to be fullyreceived at the first network node before being forwarded to the secondnetwork node. According to the present invention, however, the data unit4, or in particular a portion 41, 42 of the data unit is forwardedearly. As shown on the right side of FIG. 7, the first received portion41 of the data unit 4 is forwarded already when only this first portion41 was received. A second portion 42 of the data unit 4, and any furtherportion, is forwarded upon receiving it. The advantage of this approachis that the data unit 4 is received at the second network node earliercompared to the conventional forwarding method. The saved time isindicated by the thick black arrow in FIG. 7.

However, as described earlier, after an early forwarding of a firstportion 41 of a data unit 4, a further portion 42 of the data unit 4 mayturn out to be erroneous later. This is shown in FIG. 8. Conventionally,a data unit 4 turning out to be erroneous is simply not forwarded.However, according to the invention, the data unit 4 might already havebeen partly forwarded, i.e. a first portion 41 of the data unit 4 mighthave been forwarded earlier, as shown in FIG. 8 on the left. A furtherportion 42 of the data unit 4 then turns out to be erroneous.

To solve this problem, according to some embodiments of the presentinvention, if a first portion 41 of the data unit 4 was alreadyforwarded, this first portion 41 is marked as being speculativelyforwarded, indicated by an “s” in FIG. 8, right side. If the furtherportion 42 of the data unit 4 turns out to be erroneous, a cancelationindication is sent, indicated by a “cl” in FIG. 8, right side.

As an advantage of the method, already sent portions 41 of the data unit4, or the data unit 4 as a whole, can be cancelled. The final recipientis aware that the data unit 4 may need to be revoked.

FIG. 9 shows another implementation according to some embodiments of thecurrent invention. In particular, FIG. 9 shows the case of three networknodes being involved in the method. As shown on the left side of FIG. 9,portions 41, 42 of a not fully confirmed data unit 4 are forwarded witha speculation indication, indicated by “s” in FIG. 9, and only marked asconfirmed with a confirmation indication later, indicated by “cf” inFIG. 9.

As shown on the right side of FIG. 9, if it turns out later that thedata unit 4, or portions 41, 42 of the data unit 4, are invalid, acancellation indication is forwarded, indicated by “cl” in FIG. 9.

FIG. 10 shows another implementation according to some embodiments ofthe current invention. In particular, FIG. 10 shows an alternativehandling on a subsequent hop: As shown in FIG. 10, if a forwardedcancellation indication arrives early enough, the forwarding of a firstportion 41 of the data unit 4 can already be cancelled. This isapplicable in particular if there is some processing involved in thenetwork nodes in addition to a simple forwarding, and if thecancellation indication is forwarded quickly, e.g. as a small datapacket. Then the cancellation indication may arrive in time to avoidforwarding the first portion 41 of the data unit 4 on the next hop, asindicated by the crossed out portion 41 of the data unit 4 in FIG. 10.The cancellation indication may also easily overtake previously sentportions, if those are marked as to be forwarded with lower priority orare marked as suffering a high risk of being subject to cancellationbecause intermediate nodes will then likely forward other portionsinstead.

The extra processing is indicated by a block arrow in FIG. 10. It isdone in vain, and any additional side-effects e.g. to internal stateswill have to be cancelled or reverted as well subsequently (not shown inFIG. 10).

It should be noted that the proposed method of speculative forwarding ofa data unit in a network can easily be used in conjunction with or ontop of conventional network protocols, e.g. HARQ based onacknowledgements ACK/NACK, or any other flow and/or error controlmechanisms. In particular any additional protocols on lower layers canbe applied which are not shown in the figures and not explained indetail for the sake of clarity.

The proposed method can be applied to any processing layer from thephysical layer to the application layer in the OSI model of thecommunication protocol, or any other layered model for acknowledgedinformation exchange between two or more units.

While specific embodiments and/or details of the invention have beenshown and described above to illustrate the application of theprinciples of the invention, it is understood that this invention may beembodied as more fully described in the claims, or as otherwise known bythose skilled in the art (including any and all equivalents), withoutdeparting from such principles.

LIST OF ABBREVIATIONS

-   3GPP 3^(rd) Generation Partnership Project-   CRC Cyclic Redundancy Check-   eNB enhanced Node B-   HARQ Hybrid automatic repeat request-   HSDPA High Speed Downlink Packet Access-   LTE Long Term Evolution-   PDU Protocol Data Unit-   RNC Radio network controller-   TTI Transmission Time Interval-   UE User equipment-   UMTS Universal Mobile Telecommunications System

LIST OF REFERENCES

-   11, 13 receiving-   12 processing-   121, 15 c, forwarding-   21, 23-   14 checking-   15 a, 15 b, sending-   16, 17, 18-   19 a, 19 b assigning-   22 postponing-   24 cancelling-   25 correcting-   26 finalizing-   27 interpreting-   31, 32 network node-   311 receiving means-   312 processing means-   313 checking means-   314 a, 314 b, sending means-   314 c, 314 d,-   314 e-   315, 321 a, forwarding means-   321 b-   316 a, 316 b assigning means-   322 postponing means-   323 cancelling means-   324 correcting means-   325 finalizing means-   326 interpreting means-   4 data unit-   41, 42 portion of a data unit

The invention claimed is:
 1. A method for transmitting data in a radiocommunications system comprising: receiving a portion of a data unit ata first protocol entity; and starting a processing of the portion of thedata unit at the first protocol entity prior to receiving remainingportions of the data unit, wherein the processing comprises a forwardingof the portion of the data unit to a second protocol entity; determiningat the first protocol entity whether the data unit is valid or invalid;and determining at the first protocol entity whether to send acancellation indication, the cancellation indication indicating that theportion of the data unit is to be cancelled, wherein the cancellationindication is sent to the second protocol entity only if the data unitis deemed as invalid.
 2. The method according to claim 1, the methodfurther comprising: checking the data unit for eligibility for furtherprocessing.
 3. The method according to claim 2, wherein the checkingcomprises checking each received portion of the data unit.
 4. The methodaccording to claim 2, the method further comprising one or more of thefollowing: sending a speculation indication, the speculation indicationindicating that a recalling of the data unit could be performed in casethe checking results in the data unit not being considered eligible forfurther processing; sending a confirmation indication, the confirmationindication indicating that the checking results in the data unit beingconsidered eligible for further processing; sending an instruction forpreferred processing of the data unit, indicating a preferred processingof the data unit; sending an instruction for deferred processing of thedata unit, indicating a deferred processing of the data unit; orsending, in case of the checking indicating that a previously receivedportion of the data unit is not considered eligible for furtherprocessing, a corrective information, the corrective informationallowing for correcting the previously received portion of the dataunit.
 5. The method according to claim 1, the method further comprisingassigning an identification to the data unit, the identificationallowing to uniquely identify the data unit.
 6. The method according toclaim 1, the method further comprising assigning a likelihood value tothe data unit, the likelihood value indicating a likelihood for a needfor a correction or a cancelling of the data unit.
 7. A network nodeconfigured for transmitting data in a radio communications system, thenetwork node comprising: a memory including computer program code; aprocessor, wherein the memory and the computer program code areconfigured, with the processor, to cause the network node to performoperations comprising: receiving a portion of a data unit at a firstprotocol entity; starting a processing of the portion of the data unitat the first protocol entity prior to receiving remaining portions ofthe data unit, wherein the processing comprises a forwarding of theportion of the data unit to a second protocol entity; determining at thefirst protocol entity whether the data unit is valid or invalid; anddetermining at the first protocol entity whether to send a cancellationindication, the cancellation indication indicating that the portion ofthe data unit is to be cancelled, wherein the cancellation indication issent to the second protocol entity only if the data unit is deemed asinvalid.
 8. The network node according to claim 7, wherein the memoryand the computer program code are further configured, with theprocessor, to cause the apparatus to perform operations comprising:checking the data unit for eligibility for further processing.
 9. Thenetwork node according to claim 8, wherein the checking furthercomprises checking each received portion of the data unit.
 10. Thenetwork node according to claim 9, wherein the memory and the computerprogram code are further configured, with the processor, to cause theapparatus to perform operations comprising one or more of the following:sending a speculation indication, the speculation indication indicatingthat a recalling of the data unit could be performed in case that thechecking results in the data unit not being considered eligible forfurther processing; sending a confirmation indication, the confirmationindication indicating that the checking results in the data unit beingconsidered eligible for further processing; sending an instruction forpreferred processing of the data unit, indicating a preferred processingof the data unit; sending an instruction for deferred processing of thedata unit, indicating a deferred processing of the data unit; orsending, in case of the checking indicating that a previously receivedportion of the data unit is not considered eligible for furtherprocessing, a corrective information, the corrective informationallowing for correcting the previously received portion of the dataunit.
 11. The network node according to claim 7, wherein the memory andthe computer program code are further configured, with the processor, tocause the apparatus to perform operations comprising: assigning anidentification to the data unit, the identification allowing to uniquelyidentify the data unit.
 12. The network node according to claim 7,wherein the memory and the computer program code are further configured,with the processor, to cause the apparatus to perform operationscomprising: assigning a likelihood value to the data unit, thelikelihood value indicating a likelihood for a need for correction or acancelling of the data unit.
 13. A method for receiving data in a radiocommunications system, comprising: receiving a portion of a data unit ata second protocol entity; receiving a cancellation indication at thesecond protocol entity, the cancellation indication indicating that thedata unit has been deemed as invalid by a first protocol entity and theportion of the data unit is to be cancelled; and canceling the portionof the data unit at the second protocol entity.
 14. The method of claim13, wherein canceling the portion of the data unit comprises nullifyingthe portion of the data unit.
 15. The method of claim 13, whereincanceling the portion of the data unit comprises declaring the portionof the data unit invalid.
 16. The method of claim 13, wherein cancelingthe portion of the data unit comprises, for a database, reverting anychange done to the database corresponding to the portion of the dataunit.
 17. The method of claim 13, wherein canceling the portion of thedata unit comprises discarding information, to be sent subsequently andprepared for sending, that has been retrieved in response to the dataunit.
 18. A network node configured for receiving data in a radiocommunications system, the network node comprising: a memory includingcomputer program code; a processor, wherein the memory and the computerprogram code are configured, with the processor, to cause the apparatusto perform operations comprising: receiving a portion of a data unit ata second protocol entity; receiving a cancellation indication at thesecond protocol entity, the cancellation indication indicating that thedata unit has been deemed as invalid by a first protocol entity and theportion of the data unit is to be cancelled; and canceling the portionof the data unit at the second protocol entity.